Seal construction for steam traps

ABSTRACT

A steam trap having an improved means for sealing a control chamber within the body of the trap, particularly with respect to the inlet and outlet passages. The body of the trap has a bore with a threaded counterbore and the bore receives a cylindrical valve seat element. A beveled annular shoulder is formed between the bore and the counterbore and an adjacent beveled annular shoulder is formed in the seat so that the two shoulders together form a V-shaped annular groove that receives a radially expansible annular metal sealing gasket with a convexly curved bottom surface. The bottom surface of the gasket bears initially, when unflexed, against only the shoulder in the seating element. However, when the gasket is forced downward and outward during assembly of the trap, it is rolled and radially expanded into continuous sealing engagement with the shoulder formed between the bore and counterbore as well as with the shoulder of the valve seat element.

United States Patent 1 Goellner 51March 13, 1973 SEAL CONSTRUCTION FORSTEAM TRAPS [75] Inventor: Allan R. Goellner, Parma Heights,

Ohio

[73] Assignee: The Clark-Reliance Corp., Cleveland, Ohio [22] Filed:April12, 1971 [21] Appl. No.: 133,201

[52] U.S. Cl. ..137/183, 277/l12, 277/171 [51] Int. Cl. ..F16t 1/16 [58]Field of Search ...'....l37/l83; 251/263; 285/342;

[56] References Cited UNITED STATES PATENTS 3,073,566 l/l963Bredtschneider ..25l/363 X 3,075,793 l/l963 Lennon ..285/342 2,951,4969/1960 Yarnall ..l37/l83 Primary Examiner-Alan Cohan Attorney-B0sw0rth,Sessions, Herrstrom & Cain [57] ABSTRACT A steam trap having an improvedmeans for sealing a control chamber within the body of the trap,particularly with respect to the inlet and outlet passages. The body ofthe trap has a bore with a threaded counterbore and the bore receives acylindrical valve seat element. A beveled annular shoulder is formedbetween the bore and the counterbore and an adjacent beveled annularshoulder is formed in the seat so that the two shoulders together form'a V-shaped annular groove that receives a radially expansible annularmetal sealing gasket with a convexly curved bottom surface. The,

bottom surface of the gasket bears initially, when unflexed, againstonly the shoulder in the seating element. However, when the gasket isforced downward and outward during assembly of the trap, it is rolledand radially expanded into continuous sealing engagement with theshoulder formed between the bore and counterbore as well as with theshoulder of the valve seat element.

6 Claims, 4 Drawing Figures PATENTEUMAmmn 3,7 0,223

INVENTOR. 4444M P. aazzzA/se BY 6M, 45%;

SEAL CONSTRUCTION FOR STEAM TRAPS BACKGROUND OF THE INVENTION Thisinvention relates to steam traps for removing accumulations ofcondensate from steam systems, and especially to automatic steam trapssuch as the type disclosed in US Pat. Nos. 2,951,496 and 3,150,677.

More particularly the invention relates to an improved means for sealingthe component parts of the trap when in assembled relation so as to sealthe control chamber and particularly to prevent leakage of steam betweenthe control chamber and the outlet or the atmosphere. Such leakagecauses the trap to cycle rapidly and permits discharge of steam insteadof condensate.

Steam traps of the type to which the invention has particular utilityuse a floating disc for example located in a control chamber, to openand close the inlet and outlet passages of the trap. The floating discis adapted to contact valve seats in the control chamber to shut off theflow of fluidinto the control chamber from a steam inlet port and out ofthe control chamber through an outlet port for condensate and air. Theforce exerted against the disc by the fluid in the control chamberdetermines whether or not the disc is in contact with the seats adjacentthe ports or spaced therefrom. When air and condensate are passingthrough the trap the sealing disc is pushed away from the seatingsurfaces by the force of the fluid in the system bearing against thesealing disc. This condition permits the free flow of condensate throughthe trap. When substantially all of the condensate has passed throughthe trap, steam tends to accumulate in the control chamber behind thedisc until its pressure causes a resultant force sufficient to cause thedisc to move into contact with seats of the inlet and outlet ports.

US. Pat. No. 3,150,677 discloses a steam trap of an especiallyadvantageous design. As shown and described therein the body of the trapis provided with an inlet and outlet as well as a bore with a threadedcounterbore. The bore receives a cylindrical seating element with portstherethrough that register with the inlet and outlet passagesrespectively formed in the body of the trap. The outlet port of theseating element extends through the side thereof and the inlet portextends axially through the bottom.

The threaded counterbore of the above prior art device receives a capwith a threaded tubular shaft that defines with the top surface of theseating element,- a cylindrical control chamber. The floating disc islocated within the control chamber in a position to be seated whenclosed against the top of the seating element to close and seal both theinlet and outlet ports.

The seating element is sealed in position to prevent leakage between theinlet and outlet passages by means of a flat annular metal gasketlocated between the floor of the bore and the bottom surface of theseating element. The control chamber is sealed within the body and alsowith respect to the inletand outlet passages by means of another flatannular metal gasket positioned between the bottom edge of the cap and acarefully machined annular seat between the bore and the counterbore.The inner part of the gasket also seats against a carefully machinedannular seat formed in the top surface of the seating element at exactlythe level of the seat between the bore and counterbore.

It is apparent that in order to achieve a tight seal the surfaces of therespective annular seats must be machined to within very closetolerances. Even a slight variation could result in leakage to or fromthe valve chamber that would seriously impair the performance of thetrap. The accuracy required results in costly machining operations inthe manufacture of the trap and also makes the trap vulnerable toexcessive leakage or failure in the event that proper tolerances are notmaintained.

The construction and assembly of the various components of the trap ofthe present invention however reduce the difficulties indicated aboveand afford other features and advantages not obtainable from the priorart.

SUMMARY OF THE INVENTION it is among the objects of the invention toimprove the seals between the component parts of a steam trap of thetype generally described above.

A more specific object is to provide an improved means to seal a controlchamber for a floating disc type steam trap -within the trap body andespecially with respect to the inlet and outlet passages.

Another object of the invention is to provide an automatic steam trapthat may be assembled with improved efficiency and manufactured atrelatively low cost.

These and other objects and advantages are accomplished by means of afloating disc type steam trap having a general construction as describedabove and wherein the body of the trap is provided with a beveledannular shoulder between the bore and the counterbore and an oppositelybeveled annular shoulder formed adjacent the top of the seating elementwith the shoulder on the body being slightly below the shoulder on theseating element so that when the trap is assembled, the shoulders definean annular v-shaped groove with the legs of the V slightly offset fromeach other. An annular radially expansible gasket having a convexlycurved bottom surface is positioned in the groove and has a diameterwhen in its unexpanded or relaxed condition such that the convexlycurved bottom sur-' face rests against the beveled shoulder of theseating element. Whena cap is tightened down in the threaded counterboreduring assembly of the trap, the gasket is radially expanded and rolledabout its line of engagement with the shoulder of the seating elementuntil it is forced into sealing registration with the beveled shoulderbetween the bore and the counterbore thus providing one continuousannular seal line between the gasket and the seat and another continuousannular seal line between the gasket and the body of the trap. Theannular bottom edge of the cap according to the preferred embodiment isprovided with a convexly curved bottom edge to provide a continuous sealbetween the cap and the top surface of the expansible metal gasket. Withthis arrangement the control chamber and the inlet and outlet passagesare tightly sealed without a need for machining gasket seats toextremely close tolerances.

BRIEF DESCRIPTION OF TI-IE DRAWINGS FIG. 1 is a vertical section througha floating disc type steam trap embodying the invention;

FIG. 2 is a fragmentary sectional view similar to FIG. 1 but on anenlarged scale;

FIG. 3 is a fragmentary sectional view similar to FIG. 2 but showing theannular radially expansible sealing gasket forced into its ultimatesealing condition; and

FIG. 4 is an exploded perspective view showing the component parts ofthe steam trap of FIGS. 1 to 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly tothe drawings and initially to FIGS. 1 and 4, there is shown a floatingdisc type steam trap including a trap body preferably formed of steel,with an outlet passage 11 communicating with a threaded receptacle 12for an outlet fitting (not shown), and an inlet passage 13 communicatingwith a threaded receptacle 14 for an inlet fitting (not shown). Alsoformed in the body 10 between the passages 11 and 13 is a bore 15 with afloor 16 and a threaded counterbore 17. The outlet passage 11 terminatesin the side of the bore 15 while the inlet passage 13 terminates in thecenter of the floor 16.

A cylindrical seating element 20 is received within the bore 15 with itsbottom surface 21 adjacent the floor l6 and its top surface 22 locatedwithin the threaded counterbore 17. The seating element 20 has an outletport 23 formed therein that communicates with the outlet passage 11 inthe body 10, at one end and terminates at the other end in an annulargroove 24 formed in the top surface 22. The seating element 20 also hasan axial inlet port 25 that communicates with the inlet passage 13 inthe trap body 10 and terminates in the center of the top surface 22. Theseating element 20 is positioned in the bore 15 with its outlet port 23in proper registration with the outlet passage 1 1 by means of apositioning pin 27 that has its lower end received in a small bore 28formed in the floor 16 of the bore 15 and its upper end received in abore 29 formed in the bottom of the seating element 20.

A cap 30 having a hollow threaded shaft 31 is received in the threadedcounterbore l7 and defines with the top surface 22 of the seatingelement 20, a control chamber 32. Located within the control chamber 32is a floating disc 35 which is movable between a seated position shownin solid lines in FIG. 1 wherein it seals the annular groove 24 and theoutlet passage 23, and an open position wherein it bears against a stop36 in the top of the control chamber 32. The bottom surface of the disc35 has an annular groove 38 that is located directly over the annulargroove 24 in the seating element 20 and a small leakage duct 39 isformed between the annular groove 38 and the control chamber 32 for apurpose described in detail in US. Pat. No. 3,150,677. The seatingelement 20, cap 30 and disc 35 are preferably formed of high carbonsteel or stainless steel.

A seal is provided between the bottom surface 21 of the seating element20 and the floor 16 of the bore 15 by means of a flat annular gasket 40with annular grooves, positioned in an annular seat 41 formed in thefloor 16. The gasket 40 prevents steam from leaking around the seatingelement 20 to the outlet passage 1 1 from the inlet passage 13 and port25 of the trap body 10 and seating element 20 respectively.

The control chamber is sealed with respect to the seating element 20 andthe trap body 10 by means of a radially expansible annular sealinggasket 45 formed of annealed stainless steel or MONEIJ metal and havinga convexly curved bottom surface 46. The gasket 45 is received in aVshaped annular groove with one side wall formed by a beveled annularshoulder 47 between the bore 15 and counterbore 17 of the trap body 10and its other side wall formed by an oppositely beveled annular shoulder48 formed just adjacent the top surface 22 of the seating element 20. Asshown in the drawing, the beveled shoulder 47 is slightly below thebeveled shoulder 48, so that the legs of the V are slightly offset fromone another.

When the gasket 45 is unstressed or in other words in its originalcondition the diameter thereof is such that the convexly curved bottomsurface 46 bears only against the shoulder 48 to provide a continuousannular seal line in a circle of the annular shoulder 48 and is spacedabove the shoulder 47 as shown in FIGS. 1 and 2. When the cap 30 isturned down tightly in the threaded counterbore 17 during assembly,however, the gasket 45 is caused to expand radially and also to rolldownwardly and outwardly about the circle of contact between theconvexly curved surface 46 and the shoulder 48 until the convexly curvedsurface 46 comes into contact with the annular shoulder 47 to provide acontinuous annular seal line in a circle on the shoulder 47. A seal isalso established between the curved bottom edge of the hollow shaft 31of the cap 30 and the top surface of the gasket 45 so that threecontinuous annular seal lines are established. This condition is bestshown in FIG. 3. Furthermore the axial force caused by turning the capdown tightly into the threaded counterbore 17 urges the seating element20 firmly against the sealing gasket 40 to assure a tight seal betweenthe bottom surface 21 of the seating element 20 and the floor 16 of thebore 15. This seal is assured because the force exerted on the gasket 45is transmitted initially to the element 20 since the gasket 45 initiallyengages only the shoulder 48 and not the shoulder 47.

It will be apparent that the resulting relationship between the variousparts and the seals provided can be achieved without maintaining highlyaccurate machining tolerances with respect to the respective surfaces onwhich the seals are established. Any variations in machining accuracyare readily compensated for by the resiliency of the gasket 45,particularly by virtue of its ability to radially expand to varyingdegrees at various circumferential locations therearound and to vary inthe amount of its roll at various circumferential locations around thewedge shaped groove defined by the beveled surfaces 47 and 48.

During the operation of the trap the sealing disc 35 is moved by theaction of the fluid passing through the trap from a position in whichthe disc 35 seats against the top surface 22 of the seating element 20as shown in solid lines in FIG. 1 to a position at which it is spacedfrom the seating surfaces and wherein the central portion thereof is incontact with the stop 36 in the cap 30. After most of the condensate andair have passed through the trap the last portion thereof is at atemperature closely approaching the steam temperature of the system.Since the condensate is at such a high temperature there is a tendencyfor a portion thereof to flash into steam and this together with thekinetic energy of the fluid increases the fluid pressure acting againstthe top surface of the disc 35 until the total force acting against thetop surface of the disc 35 becomes greater than the force acting on thebottom surface thereof and thereby the disc 35 is forced into contactwith the top surface 22 of the seating element to close the trap.Closing of the trap may even occur through the unit pressure in thechamber 32 may be less than the unit pressure in the system.

The disc 35 will remain in contact with the seating element 20 until thefluid pressure in the chamber 32 is reduced to the point that the forceacting against the top surface of the disc is less than the effectiveforce exerted against the bottom surface thereof. This reduction inpressure is largely the result of the heat energy transferred to thesurrounding atmosphere and the fluid which escapes through the bleederpassage 39 connecting the annular groove 38 with the control chamber 32.The bleeder passage 39 is desirable to insure the opening and closing ofthe trap at sufficiently frequent intervals and prevention of possibletrapping of air above the disc. The function and advantages obtained bythe bleeder passage 39 are presented in more detail in U.S. Pat. No.3,150,677 and form no part of the present invention.

While the invention has been illustrated and described with respect to aspecific embodiment thereof this in intended for the purpose ofillustration rather than limitation and other forms and modificationswill be apparent to those skilled in the art upon a reading of thespecification and appended claims. Wherefore the patent is not to belimited in any way that is inconsistent with the extent to which theprogress in the art has been advanced by the invention.

I claim:

1. A seal for an annular joint between a body having a bore and acylindrical element received in said bore and having a circular end facefacing away from said bore, said seal comprising a beveled annularshoulder on said element at the edge of said circular end face and abeveled annular shoulder at the edge of said bore location adjacent toandslightly below and radially outward from said shoulder on saidelement, said shoulders defining with one another a V shaped groove, a

radially expansible gasket having a convexly curved bottom surface thatfits in said groove and that initially bears circumferentially onlyagainst said shoulder of said element when said gasket is in itsoriginal condition, and said gasket when forced downwardly into saidgroove being expanded and rolled downwardly and outwardly into sealingengagement with said beveled shoulder of said body to provide acontinuous annular seal between said gasket and said body and anothercontinuous seal between said gasket and said element.

2. A seal according to claim 1 having a gasket composed of steel.

3. A seal according to claim 2 wherein the top surface of the gasket isflat.

4. In a steam trap including a body having a sealed control chambertherein, a valve seating element secured within said body and having acircular end face within said control chamber, a port in said seatingelement opening into said control chamber, and valve means in saidcontrol chamber for controlling the opening and closing of said port,the improvement which comprises:

a beveled annular shoulder on said seating element at the edge of saidcircular end face, a bevele annular shoulder in said body locatedradially outward from and adjacent to and slightly below said shoulderin said seat element, said shoulders defining with one another a Vshaped annular groove with the legs of the V slightly offset from oneanother,

an annular, radially expansible gasket having a convexly curved bottomsurface that fits in said groove and that initially bearscircumferentially only against said shoulder of said seating element andis spaced from said shoulder in said body when said gasket is in itsoriginal condition, and

means for forcing said gasket downwardly into said groove whereby saidgasket is advanced downwardly and outwardly into sealing engagement withsaid beveled shoulder of said body to provide a continuous annular sealline between said gasket and said body and another continuous annularseal line between said gasket and said seating element.

5. A steam trap as defined in claim 4 wherein said gasket has a flat topsurface and said bore has a threaded counterbore and wherein said meansfor forcing said gasket downwardly comprises a cap with a threadedhollow shaft received in said threaded counterbore and having a curvedannular bottom edge that makes sealing engagement with the flat topsurface of said gasket.

6. In a steam trap having a body with a bore with a threadedcounterbore, a cylindrical valve seating element positioned in saidbore, an annular sealing gasket between the bottom of said seatingelement and the floor of said bore, a cap with a hollow shaft threadedlyreceived in said bore to define with said seat a control chamber, afirst port in said seating element communicating with said controlchamber and a second port in said seating element communicating withsaid control chamber and valve means in said control chamber forcontrolling the opening and closing of said ports,;the improvement whichcomprises:

a convexly curved annular edge surface formed at the bottom of said cap,

a beveled annular shoulder in said body between said bore and saidcounterbore,

a beveled annular shoulder on said seating element adjacent saidshoulder in said body being slightly below said shoulder on said seatingelement, said shoulders defining with one another a V shaped annulargroove with the legs of the V slightly offset from one another, and anannular, radially expansible gasket with its top surface sealinglyengageable by said annular edge and having a convexly curved bottomsurface that rests against said shoulder on said seating element whensaid gasket is unexpanded and that advances downwardly and outwardlyinto sealing engagement with said shoulder of said body when said cap istightened down, the force exerted by said radially expansible gasket onsaid seating element urging said seating element into sealing engagementwith thesaid gasket that is disposed between the bottom of the seatingelement 'and the floor of said bore.

1. A seal for an annular joint between a body having a bore and acylindrical element received in said bore and having a circular end facefacing away from said bore, said seal comprising a beveled annularshoulder on said element at the edge of said circular end face and abeveled annular shoulder at the edge of said bore location adjacent toand slightly below and radially outward from said shoulder on saidelement, said shoulders defining with one another a V shaped groove, aradially expansible gasket having a convexly curved bottom surface thatfits in said groove and that initially bears circumferentially onlyagainst said shoulder of said element when said gasket is in itsoriginal condition, and said gasket when forced downwardly into saidgroove being expanded and rolled downwardly and outwardly into sealingengagement with said beveled shoulder of said body to provide acontinuous annular seal between said gasket and said body and anothercontinuous seal between said gasket and said element.
 1. A seal for anannular joint between a body having a bore and a cylindrical elementreceived in said bore and having a circular end face facing away fromsaid bore, said seal comprising a beveled annular shoulder on saidelement at the edge of said circular end face and a beveled annularshoulder at the edge of said bore location adjacent to and slightlybelow and radially outward from said shoulder on said element, saidshoulders defining with one another a V shaped groove, a radiallyexpansible gasket having a convexly curved bottom surface that fits insaid groove and that initially bears circumferentially only against saidshoulder of said element when said gasket is in its original condition,and said gasket when forced downwardly into said groove being expandedand rolled downwardly and outwardly into sealing engagement with saidbeveled shoulder of said body to provide a continuous annular sealbetween said gasket and said body and another continuous seal betweensaid gasket and said element.
 2. A seal according to claim 1 having agasket composed of steel.
 3. A seal according to claim 2 wherein the topsurface of the gasket is flat.
 4. In a steam trap including a bodyhaving a sealed control chamber therein, a valve seating element securedwithin said body and having a circular end face within said controlchamber, a port in said seating element opening into said controlchamber, and valve means in said control chamber for controlling theopening and closing of said port, the improvement which comprises: abeveled annular shoulder on said seating element at the edge of saidcircular end face, a beveled annular shoulder in said body locatedradially outward from and adjacent to and slightly below said shoulderin said seat element, said shoulders defining with one another a Vshaped annular groove with the legs of the V slightly offset from oneanother, an annular, radially expansible gasket having a convexly curvedbottom surface that fits in said groove and that initially bearscircumferentially only against said shoulder of said seating element andis spaced from said shoulder in said body when said gasket is in itsoriginal condition, and means for forcing said gasket downwardly intosaid groove whereby said gasket is advanced downwardly and outwardlyinto sealing engagement with said beveled shoulder of said body toprovide a continuous annular seal line between said gasket and said bodyand another continuous annular seal line between said gasket and saidseating element.
 5. A steam trap as defined in claim 4 wherein saidgasket has a flat top surface and said bore has a threaded counterboreand wherein said means for forcing said gasket downwardly comprises acap with a threaded hollow shaft received in said threaded counterboreand having a curved annular bottom edge that makes sealing engagementwith the flat top surface of said gasket.